During training camp, Mike Woodson revealed Iman Shumpert experienced knee pain over the summer and had battled with some of his old injuries.

A league source confirmed Shumpert actually had arthroscopic surgery on his left knee, which was not announced by the Knicks. According to the source, the procedure occurred in mid-to-late August. It was on the same knee in which he tore his ACL and meniscus during the 2012 playoffs. But a source said the clean-out was so minor he didn’t need crutches afterward. However, the team didn’t announce it, abiding by Shumpert’s wishes.

A source said the surgery’s late date wasn’t good timing because it ruined the chance for Shumpert to participate in a portion of the offseason workout program with the assistant coaches and the early part of voluntary scrimmages at the Knicks’ training center. The workout program was considered vital because Shumpert elected to play in just one summer-league game in Las Vegas in July because of a conflict with a trip to China.

The Knicks are shopping Shumpert to see whether they can alleviate a shooting-guard glut and add frontcourt help. They are concerned more about Shumpert’s attitude at this point than his knee.

The Knicks have inquired about Celtics point guard Rajon Rondo and Houston’s Omer Asik. Rondo is the player Carmelo Anthony had told confidants he hoped the team could pry from Boston over the summer.

However, neither the Rockets nor Celtics have interest in a deal because the Knicks don’t have draft picks to add to a package.

“[There’s] nothing I can really do,” Shumpert said Sunday at a Citi basketball pro camp in Mount Vernon. “If they trade me, they trade me. It’s not really in my control. All I know is I’m on the Knicks right now, [and] I have to play hard for the Knicks.”

Shumpert said in recent days he hasn’t looked at his Twitter feed.

“I just turn Twitter off on my phone,’’ Shumpert said after Saturday’s loss to Atlanta. “I don’t’ watch much TV.’’

Shumpert hasn’t missed a game this season, but had nagging injuries during the preseason, including calf and shoulder strains. Sources have said he has fallen out of favor with Woodson.

“Right now we’re not in a shooting rhythm and the worse it gets, the more we’re trying to put more on the shoulders of our scorer,’’ Shumpert said. “We can’t beat him up like that. We got to get easy buckets for him.’’

With the Knicks reeling at 3-6, Shumpert said the season is still young.

“I think we need to just win a game — string ’em together and everybody will calm down,” he said.
Shumpert said he believes brighter times are ahead.

“It’s early in the season. I’ve been through worse,” he said. “My rookie year, we lost [11-of-13] and then we became the hot team. People don’t even remember that. When we hit rock bottom, we’ll make it out. We can’t panic.’’

When asked to evaluate his season, Shumpert said, “It’s been disappointing so far, because we haven’t taken care of business at home. But we will. We’ll get it done.”

Last week, the Knicks were trying to trade Shumpert to the Nuggets for power forward Kenneth Faried and had talked to Sacramento about Jason Thompson. Sources say the Nuggets weren’t interested.

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The funeral for Metta World Peace’s sister, Shalice Holmes-Taylor, was Sunday. She had battled cancer the past eight months. The service was attended by Knicks executives Steve Mills and Allan Houston. It was not the reason World Peace sat out Saturday’s game. He’s battling a sore knee but is expected back Tuesday in Detroit.